1. Field of the Art
This invention relates to a fluid supply conduit system suitable for use on medical endoscopes in charging and discharging a fluid to and from a body cavity, and more particularly to an endoscopic conduit system capable of supplying a fluid selectively either from a fluid supply source connected to a fluid feed port on a manipulating head assembly of an endoscope or from a fluid supply source connected to a universal cable of the endoscope.
2. Prior Art
Generally, medical endoscopes are largely constituted by a manipulating head assembly to be gripped and manipulated by an operator for controlling various endoscopic operations, an elongated insertion tube connected to a front side of the manipulating head assembly for insertion into a body cavity of a patient, and a universal cable led out on the rear side of the manipulating head assembly. The universal cable is disconnectibly connectible at least to a light source to transmit illumination light to the fore distal end of the insertion tube through a light guide. In addition to the light guide, various channels and passages are provided internally of the endoscope.
As for example of internal passages or channels, in many cases the so-called biopsy channel is provided in endoscopes to permit insertion of forceps or other biopsy or surgical instruments. The biopsy channel extends through the endoscope toward an exit opening which is opened at the distal end of the insertion tube. In addition, a suction channel is provided for aspiration of body fluids or the like. Normally, a suction channel is provided within an endoscope in communication with the biopsy channel. An aspirator with a vacuum pump device is connected to the other proximal end of the suction channel at the time of aspiration. A suction valve which is provided on the manipulating head assembly of the endoscope is connected to the suction channel and is manipulated by an operator at the time of starting or ending aspiration.
Further, a cleaning fluid supply channel is provided in the endoscope for the purpose of supplying cleaning fluids to be used in cleaning or washing an observation window which is provided at the fore distal end of the insertion tube. The cleaning fluid normally consists of a cleaning liquid (normally cleaning water) and compressed air. When an observation window is contaminated, a cleaning liquid is spurted toward the observation window to wash away contaminants therefrom. Thereafter, compressed air is supplied and blasted against the observation window to remove droplets of the cleaning liquid. Thus, for this purpose, a liquid feed channel and an air feed channel are provided in the endoscope. An air/water feed valve which is provided on the manipulating head assembly of the endoscope is operated by an operator at the time of supplying a cleaning liquid and compressed air to the liquid and air feed channels. The liquid feed channel and the air feed channel are joined together in the vicinity of the fore distal end of the insertion tube and connected to a spout nozzle which is directed toward the observation window. The air/water feed valve is put in a liquid feed position, whereupon a cleaning liquid is supplied to the spout nozzle and spurted toward the observation window. In the next place, the air/water feed valve is put in an air feed position, whereupon a jet of compressed air is spurted out from the nozzle. Thus, an observation window at the fore distal end of the endoscopic insertion tube can be washed clean without necessitating one to extract the insertion tube each time when it is found to be contaminated.
Further, in addition to the channels for the observation window cleaning operations, some endoscopes are provided with a fluid jet injection channel for injecting a jet of water toward an intracavitary wall under high pressure for washing purposes or for sprinkling a pigment on an intracavitary wall or for feeding or circulating a cleaning liquid to internal portions. Such a jet injecting channel is connected to an injection port which is opened at the fore distal end of the insertion tube to inject a cleaning water or a medicinal liquid.
In this connection, it has been the usual practice to employ a pump for supplying a large quantity of fluids to the injection port of the fluid jet injection channel from a supply tank. At this time, the other end of the channel is connected to a fluid supply tank and a pump. Since a universal cable is led out from the manipulating head assembly, from the standpoint of maneuverability of the manipulating head assembly, it is rather desirable to pass the fluid jet injection channel through the universal cable. However, in some cases the pump pressure is found insufficient to supply a fluid under a predetermined pressure. In this regard, it has been known in the art to boost the fluid supply pressure with a fluid from a syringe at the time of injecting a fluid from a passage from a pressure feed means which is connected to the fluid jet injection channel, for example, as disclosed in Laid-Open Japanese Patent Application H11-32988.
The purposes of use of the fluid jet injection channel include not only supply of a large quantity of a cleaning or wash water but also supply of a small amount of a coloring matter or a pigment under high pressure. At the time of supplying a required amount of a fluid under high pressure, it is desirable to pump in the fluid from the side of the manipulating head assembly by an operator using a syringe or a similar pressure feed means. However, in the case of the above-mentioned prior art, a syringe or a pressure feed means which is set on the manipulating head assembly of the endoscope is used as an auxiliary means for boosting the pressure of a fluid which is supplied through a fluid supply channel on the side of the universal cable, and not used as means for supplying a fluid from the side of manipulating head assembly independently of a pump. It follows that other fluid feed means becomes necessary for supplying a small amount of a medicinal solution under high pressure. Namely, the fluid injection channel of the above-mentioned prior art is not suitable for use in such cases where a necessary amount of a fluid has to be supplied under a certain pressure according to judgements of an operator.